Today at noon PT / 3 pm ET, I’ll talk with Sierra magazine’s senior editor Paul Rauber about the rooftop farms springing up across New York City. Please join us. The occasion is “Up on the Farm,” a feature story I wrote for the magazine’s November/December issue. Back in July, during a steamy heat wave, I visited two rooftop farms, Brookyn Grange and Gotham Greens — pioneering urban farms with drastically different approaches to feeding the city. […]